This application claims priority from Korean Patent Application No. 2003-81109, filed on Nov. 17, 2003, in the Korean Intellectual Property Office, the contents of which are incorporated herein in their entirety by reference.
1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device having a sense amplifier driver including a metal oxide semiconductor (MOS) capacitor affected by the off current of a semiconductor device manufactured under a high temperature by a fast manufacturing process.
2. Description of the Related Art
FIG. 1 is a conventional memory cell used in a semiconductor memory device. With reference to FIG. 1, the memory cell 10 is made up of a transistor 11 and a capacitor 12.
In general, the gate of the transistor 11 is connected to a word line WL, one terminal of the transistor 11 is connected to a bit line BL, and the capacitor 12 to store data is connected between the other terminal of the transistor 11 and the ground voltage VSS.
As deep submicron technology continues to be developed, the threshold voltage of transistors such as the one used as the transistor 11 is getting lower, thus improving the performance thereof. The performance of the transistor 11 can be expressed by the amount of current Idsat that the transistor 11 can conduct in a turn-on state.
If the threshold voltage of the transistor 11 is lower, the amount of current Idsat that the transistor 11 can conduct in the turn-on state (hereinafter, on current) increases. However, the amount of leakage current Ioff conducting in the transistor 11 in a turn-off state (hereinafter, off current) increases.
In general, the off current Ioff changes according to the manufacturing temperature, the voltage, and the manufacturing process. The manufacturing process includes a fast process and a slow process. For example, a transistor in which the on current Idsat is large can be manufactured by a fast process and a transistor in which the on current Idsat is small can be manufactured by a slow process.
However, under specific conditions (for example, a high manufacturing temperature and fast manufacturing process), the off current off increases so much that the on current Idsat is affected. Particularly, in an array including a plurality of memory cells, the merit obtained by lowering the threshold voltage of the memory cell dramatically decreases due to the decrease in the difference between the on current Idsat and the off current Ioff in the high manufacturing temperature and fast manufacturing process conditions.
When a memory device having a memory cell is designed, the amount by which the threshold voltage of the memory cell can be lowered is limited by the off current.